What cells will you see in joint with immune-mediated arthritis?

• A. Lymphocytes
• B. Eosinophils
• C. Neutrophils
• D. Macrophages

Answer: (D)

Immune-mediated arthritis features chronic inflammation within the joint driven by immune cells. Macrophages infiltrate the synovium and are central players: they accumulate in the joint, release inflammatory cytokines, present antigen, and drive tissue destruction and pannus formation. Neutrophils are more typical of acute or septic arthritis, while eosinophils and lymphocytes can appear in other contexts. The prominence and central role of macrophages in sustained synovitis make them the best match for immune-mediated arthritis in the joint.